Packaging materials and structures for compositions including an exothermic agent and a volatile agent

ABSTRACT

Packaging materials and structures for compositions including an exothermic agent and a volatile agent are described. The package material includes a polymeric sealing layer which includes a non-ionic polymer or a polymer comprising ionic groups fewer than 10 percent of which (e.g., fewer than 1% of which) have been neutralized. The volatile agent can be an agent that emits a fragrance or aroma such as menthol, eucalyptus and/or camphor vapors. The composition can also include an effervescent agent. The package structures are resistant to discoloration caused by interaction with the product. The package structures also have high moisture barrier properties and can be formed and sealed at high speed.

BACKGROUND

1. Technical Field

This application relates generally to packaging materials and structures and, in particular, to packaging materials and structures for compositions comprising an exothermic agent and a volatile agent (e.g., an agent which emits menthol, eucalyptus and/or camphor vapors).

2. Background of the Technology

U.S. Pat. No. 5,993,854 describes an exothermic effervescent composition designed for improved fragrance dispersion. This technology has been used as the basis for tableted products that distribute menthol, eucalyptus, camphor and other related vapors in the shower. Consumers appreciate this particular combination of ingredients for their ability to soothe their sinuses.

Since this product is designed to be reactive with water, it must be manufactured and packaged in ways that minimize contact with even the smallest amounts of moisture. The product is so sensitive to moisture that the air in the manufacturing environment must be controlled to minimize ambient humidity. In fact, this environment is maintained at humidity levels below 20 grains of moisture per pound of dry air.

Not only does the manufacturing environment need to be controlled for low humidity, the product must be packaged in such a way that ambient humidity cannot come in contact with it until the consumer is ready to use it. This can be accomplished by using packaging materials that are highly resistant to permeation by water vapor. Laminated flexible films that include a layer of aluminum foil are particularly well suited for this task.

Since this type of product is packaged at a very high rate of speed, the packaging equipment and material should be chosen and designed so that moisture proof seals can be attained easily. In order to accomplish this, the inner layer of the package film laminate can be a sealing material that melts very rapidly and forms a complete seal when it is pressed on to itself. There are many materials used for this purpose. The material used for a particular product is typically chosen based on the machinery being used and the nature of the product itself.

Many products contain ingredients that may interact with the packaging material. Ingredients that can dissolve, abrade or otherwise damage the packaging material are obviously incompatible with it. It is also important that the product not react with components of the packaging material. Reaction between the product and the packaging material may result in degradation of the product and/or of the packaging material.

There still exists a need for improved packaging materials, particularly for moisture sensitive compositions and for compositions containing a volatile component.

SUMMARY

According to a first embodiment, an article of manufacture is provided which comprises: a composition comprising a volatile agent and an exothermic agent; and a packaging material in contact with the composition, the packaging material comprising a polymer, wherein the polymer is a non-ionic polymer or a polymer comprising ionic groups fewer than 10 percent of which have been neutralized.

According to a second embodiment, a method is provided which comprises: enclosing a composition comprising a volatile agent and an exothermic agent in one or more layers of a packaging material, wherein the packaging material includes a sealing layer comprising a non-ionic polymer or a polymer comprising ionic groups fewer than 10 percent of which have been neutralized; and sealing the one or more layers of the packaging material together by applying heat and pressure.

DETAILED DESCRIPTION

Moisture sensitive products are often packaged in flexible films that provide high barriers to water vapor penetration. These films are laminated structures that can include a moisture barrier layer such as an aluminum foil layer, a sealing layer and possibly other layers depending on their intended use.

Aside from the aluminum foil layer, which provides the majority of resistance to moisture penetration, the sealing layer is typically the most important part of the film laminate structure. This layer should be able to be melted rapidly due to the high speed of the equipment that is used to wrap it around the product and then it should solidify quickly when it is pressed against itself. Sealing-layer materials that can perform these functions well form good, moisture proof seals.

Since the sealing layer comes in direct contact with the product, it is important that it be compatible with the product that it is protecting. Moreover, the sealing layer should not cause damage to the product and, conversely, the product should not damage the sealing layer in any way that degrades its ability to perform its function. As set forth above, many products contain ingredients that may interact with the packaging material (i.e., the sealing material). As with packaging materials generally, ingredients that can dissolve, abrade, discolor or otherwise damage a sealing layer are obviously incompatible with it.

As set forth above, an exothermic effervescent tablet product that contains a fragrance comprised of menthol, eucalyptus oil and camphor was developed as a sinus treatment for use in the shower. Magnesium chloride can be incorporated in the product as the exothermic agent. When this material comes in contact with moisture, it releases a great deal of heat (i.e., approximately 36 kcal per gram-mole) as it hydrates. Citric acid and sodium carbonate can be used to provide the effervescence. Since water starts the effervescent reaction and releases heat from the exothermic agent, it is important that the package provide adequate protection from exposure to moisture.

A suitable sealing material typically used for this type of moisture barrier packaging is Surlyn® 1652, manufactured by DuPont. This material has been used successfully on similar products that are manufactured at speeds similar to those employed for this one. Chemically, Surlyn® is an ethylene methacrylic acid (E/MAA) copolymer that has been neutralized with either zinc or sodium. Surlyn® 1652 is neutralized with zinc. Polymers of this type are disclosed in U.S. Pat. No. 3,264,272.

During the development of the product, it was noted that many tablets developed brown spots where the Surlyn® layer of the film came in contact with the product. Experimentation showed that this discoloration was caused by an interaction between the Surlyn® and various specific components of the product.

This application is directed to packaging compositions that do not exhibit this interaction with the product. Surprisingly, it was found that when E/MAA copolymer sealants that are not neutralized are utilized, the discoloration observed with Surlyn® does not occur. It has also been found that other non-neutralized sealing polymers can also be used without causing discoloration.

Experiments were conducted to determine which materials in the composition caused the discoloration and to identify sealing layers that would not discolor upon contact with the product. Results from an experiment that investigated various alternate sealing layers are set forth in the table below. Sealing Layer Result Surlyn ® 1652 E/MAA copolymer Discoloration No sealing layer (bare aluminum foil) No discoloration Co-extruded EAA/LDPE No discoloration Nucrel ® 1214 E/MAA copolymer No discoloration Nucrel ® 0910 E/MAA copolymer No discoloration Nucrel ® 3390 EAA copolymer No discoloration In the above table, “E/MAA” denotes ethylene/methacrylic acid, “EAA” denotes ethylene/acrylic acid and “LDPE” denotes low density polyethylene. The Nucrel® polymers employed in these experiments comprise repeat units derived from acrylic acid or methacrylic acid. Unlike the Surlyn® polymers, however, these polymers have not been neutralized by reaction with an ionizable metal compound such as sodium or magnesium. Polymers of this type are disclosed in U.S. Pat. No. 4,351,931.

A second set of experiments attempted to determine which, if any, of the ingredients in the exothermic tablet could be identified as a cause for the discoloration. These tablets were wrapped with Surlyn® lined film. Data from this experiment is set forth in the table below: Sample Result Full product (control) Discoloration Product without exothermic agent (MgCl₂) No discoloration Product without menthol/camphor/eucalyptus fragrance No discoloration Considering both sets of experiments leads to the conclusion that the combination of Surlyn®, magnesium chloride and the menthol/camphor/eucalyptus or other volatile fragrance causes the discoloration found on the tablets.

Since the Nucrel® copolymers are very similar chemically to the Surlyn® material (i.e., the Nucrel® polymers are not neutralized whereas the Surlyn® polymers are neutralized), it can be concluded that the ionic nature of the Surlyn® polymers is playing a significant role in causing the discoloration.

Various non-limiting exemplary embodiments are described below.

According to a first embodiment, an article of manufacture is provided which comprises: a composition comprising a volatile agent and an exothermic agent; and a packaging material in contact with the composition, the packaging material comprising a polymer, wherein the polymer is a non-ionic polymer or a polymer comprising ionic groups fewer than 10 percent (preferably fewer than 1 percent) of which have been neutralized.

According to a second embodiment, a method is provided which comprises: enclosing a composition comprising a volatile agent and an exothermic agent in one or more layers of a packaging material, wherein the packaging material includes a sealing layer comprising a non-ionic polymer or a polymer comprising ionic groups fewer than 10 percent (preferably fewer than 1 percent) of which have been neutralized; and sealing the one or more layers of the packaging material together by applying heat and pressure.

According to any of the aforementioned embodiments, the polymer can be a polymer comprising ionic groups fewer than 1 percent of which have been neutralized. The composition can be in tablet form. The packaging material can be a laminate comprising a moisture barrier layer and a layer comprising the polymer, wherein the layer comprising the polymer is in contact with the composition. The moisture barrier layer can be a metal (e.g., aluminum) foil or a metallized film layer. The packaging material can enclose the composition. For example, one or more layers of packaging material can be sealed together via the layer comprising the polymer.

The polymer can comprise ionic groups fewer than 10 percent of which have been neutralized. For example, the polymer can include a repeat unit derived from the free radical polymerization of acrylic acid or methacrylic acid. Exemplary polymers include, but are not limited to, a copolymer of ethylene and acrylic acid or a copolymer of ethylene and methacrylic acid. The polymer can also be a non-ionic polymer. Exemplary non-ionic polymers include, but are not limited to: polyvinyl acetate, polyvinyl butyral, a fluorinted polyolefin, fluorinated ethylene propylene, polytetrafluoroethylene, polyvinylidene fluoride, ethyl vinyl acetate, ethylene acrylate, acid modified ethylene acrylate, anhydride modified ethylene acrylate, acid or acrylate modified ethyl vinyl acetate, high density polyethylene, anhydride modified high density polyethylene, linear low density polyethylene, anhydride modified linear low density polyethylene, polypropylene, anhydride modified polypropylene, polyethylene, low density polyethylene, polyvinyl alcohol, an acrylic copolymer, ethyl butyl acrylate, ethyl ethyl acrylate, ethyl methyl acrylate, polyester, and amorphous nylon.

The volatile agent can emit a fragrance or aroma. For example, the volatile agent can emit menthol, eucalyptus and/or camphor vapors.

Exemplary exothermic agents include, but are not limited to, magnesium chloride, magnesium sulfate, ferric chloride, aluminum sulfate hexahydrate, and aluminum chloride.

The composition further can further include an effervescent agent. Exemplary effervescent agents include, but are not limited to, compositions comprising an alkaline carbonate salt and an acid. Exemplary alkaline carbonate salts for the effervescent agent include, but are not limited to, sodium bicarbonate, sodium carbonate, sodium sesquicarbonate, potassium bicarbonate, potassium carbonate, potassium sesquicarbonate, magnesium carbonate, ammonium bicarbonate, ammonium carbonate, ammonium sesquicarbonate, and calsium carbonate. Exemplary acids for the effervescent agent include, but are not limited to, formic acid, acetic acid, propanoic acid, butyric acid, valeric acid, oxalic acid, malonic acid, tartaric acid, succinic acid, glutaric acid, adipic acid, glycolic acid, aspartic acid, pimelic acid, fumaric acid, maleic acid, phthalic acid, isophthalic acid, terphthalic acid, glutamic acid, lactic acid, hydroxy acrylic acid, alpha hydroxy butyric acid, glyceric acid, tartronic acid, hydroxy benzoic acid, citric acid, salicylcic acid, gallic acid, mandelic acid, tropic acid, ascorbic acid, gluconic acid, cinnamic acid, benzoic acid, phenylacetic acid, nicotinic acid, kainic acid, sorbic acid, pyrrolidone carboxylic acid, trimellitic acid, benzene sulfonic acid, toluene sulfonic acid, potassium dihydrogen phosphate, sodium sulfite, sodium dihydrogen phosphate, potassium sulfite, sodium pyrosulfite, acidic sodium hexametaphosphate, acidic potassium hexametaphosphate, acidic sodium pyrophosphate, acidic potassium pyrophosphate, sulfamic acid and phosphoric acid.

The composition can be an exothermic effervescent composition as disclosed in U.S. Pat. No. 5,993,854, which is incorporated by reference herein in its entirety.

While the foregoing teaches the principles of the present invention, with examples provided for the purpose of illustration, it will be appreciated by one skilled in the art from reading this disclosure that various changes in form and detail can be made without departing from the true scope of the invention. 

1. An article of manufacture comprising: a composition comprising a volatile agent and an exothermic agent; and a packaging material in contact with the composition, the packaging material comprising a polymer, wherein the polymer is a non-ionic polymer or a polymer comprising ionic groups fewer than 10 percent of which have been neutralized.
 2. The article of manufacture of claim 1, wherein the packaging material is a laminate comprising a moisture barrier layer and a layer comprising the polymer, wherein the layer comprising the polymer is in contact with the composition.
 3. The article of manufacture of claim 2, wherein the moisture barrier layer comprises a metal foil or a metallized film layer.
 4. The article of manufacture of claim 3, wherein the moisture barrier layer comprises an aluminum foil layer.
 5. The article of manufacture of claim 1, wherein the packaging material encloses the composition.
 6. The article of manufacture of claim 2, wherein one or more layers of packaging material are sealed together via the layer comprising the polymer.
 7. The article of manufacture of claim 1, wherein the polymer comprises a repeat unit derived from the free radical polymerization of acrylic acid or methacrylic acid.
 8. The article of manufacture of claim 1, wherein the polymer is a copolymer of ethylene and acrylic acid or a copolymer of ethylene and methacrylic acid.
 9. The article of manufacture of claim 1, wherein the polymer is a non-ionic polymer.
 10. The article of manufacture of claim 9, wherein the polymer is selected from the group consisting of: polyvinyl acetate, polyvinyl butyral, a fluorinted polyolefin, fluorinated ethylene propylene, polytetrafluoroethylene, polyvinylidene fluoride, ethyl vinyl acetate, ethylene acrylate, acid modified ethylene acrylate, anhydride modified ethylene acrylate, acid or acrylate modified ethyl vinyl acetate, high density polyethylene, anhydride modified high density polyethylene, linear low density polyethylene, anhydride modified linear low density polyethylene, polypropylene, anhydride modified polypropylene, polyethylene, low density polyethylene, polyvinyl alcohol, an acrylic copolymer, ethyl butyl acrylate, ethyl ethyl acrylate, ethyl methyl acrylate, polyester, and amorphous nylon.
 11. The article of manufacture of claim 1, wherein the volatile agent emits a fragrance or aroma.
 12. The article of manufacture of claim 11, wherein the volatile agent emits menthol, eucalyptus and/or camphor vapors.
 13. The article of manufacture of claim 1, wherein the exothermic agent is selected from the group consisting of magnesium chloride, magnesium sulfate, ferric chloride, aluminum sulfate hexahydrate, and aluminum chloride.
 14. The article of manufacture of claim 1, wherein the composition further comprises an effervescent agent.
 15. The article of manufacture of claim 14, wherein the effervescent agent comprises an alkaline carbonate salt and an acid.
 16. The article of manufacture of claim 15, wherein the alkaline carbonate salt is selected from the group consisting of sodium bicarbonate, sodium carbonate, sodium sesquicarbonate, potassium bicarbonate, potassium carbonate, potassium sesquicarbonate, magnesium carbonate, ammonium bicarbonate, ammonium carbonate, ammonium sesquicarbonate, and calsium carbonate.
 17. The article of manufacture of claim 15, wherein the acid is selected from the group consisting of formic acid, acetic acid, propanoic acid, butyric acid, valeric acid, oxalic acid, malonic acid, tartaric acid, succinic acid, glutaric acid, adipic acid, glycolic acid, aspartic acid, pimelic acid, fumaric acid, maleic acid, phthalic acid, isophthalic acid, terphthalic acid, glutamic acid, lactic acid, hydroxy acrylic acid, alpha hydroxy butyric acid, glyceric acid, tartronic acid, hydroxy benzoic acid, citric acid, salicylcic acid, gallic acid, mandelic acid, tropic acid, ascorbic acid, gluconic acid, cinnamic acid, benzoic acid, phenylacetic acid, nicotinic acid, kainic acid, sorbic acid, pyrrolidone carboxylic acid, trimellitic acid, benzene sulfonic acid, toluene sulfonic acid, potassium dihydrogen phosphate, sodium sulfite, sodium dihydrogen phosphate, potassium sulfite, sodium pyrosulfite, acidic sodium hexametaphosphate, acidic potassium hexametaphosphate, acidic sodium pyrophosphate, acidic potassium pyrophosphate, sulfamic acid and phosphoric acid.
 18. The article of manufacture of claim 1, wherein the polymer is a polymer comprising ionic groups.
 19. The article of manufacture of claim 18, wherein fewer than 1 percent of the ionic groups of the polymer have been neutralized.
 20. The article of manufacture of claim 1, wherein the composition is in tablet form, and comprises magnesium chloride and a volatile agent that emits at least one of menthol, eucalyptus or camphor vapors.
 21. A method comprising: enclosing a composition comprising a volatile agent and an exothermic agent in one or more layers of a packaging material, wherein the packaging material includes a sealing layer comprising a non-ionic polymer or a polymer comprising ionic groups fewer than 10 percent of which have been neutralized; and sealing the one or more layers of the packaging material together by applying heat and pressure thereto.
 22. The method of claim 21, wherein the composition is in tablet form.
 23. The method of claim 21, wherein the polymer is a polymer comprising ionic groups.
 24. The method of claim 23, wherein fewer than 1 percent of the ionic groups of the polymer have been neutralized.
 25. The method of claim 21, wherein the packaging material is a laminate comprising a moisture barrier layer and a layer of the polymer.
 26. The method of claim 25, wherein the moisture barrier layer comprises a metal foil or a metallized film layer.
 27. The method of claim 21, wherein the volatile agent emits a fragrance or aroma.
 28. The method of claim 27, wherein the volatile agent emits menthol, eucalyptus and/or camphor vapors.
 29. The method of claim 21, wherein the exothermic agent is selected from the group consisting of magnesium chloride, magnesium sulfate, ferric chloride, aluminum sulfate hexahydrate, and aluminum chloride.
 30. The method of claim 21, wherein the composition further comprises an effervescent agent.
 31. The method of claim 23, wherein the polymer comprises a repeat unit derived from the free radical polymerization of acrylic acid or methacrylic acid.
 32. The method of claim 31, wherein the polymer is a copolymer of ethylene and acrylic acid or a copolymer of ethylene and methacrylic acid.
 33. The method of claim 21, wherein the exothermic agent comprises magnesium chloride and wherein the volatile agent emits at least one of menthol, eucalyptus or camphor vapors 